Compass-deviation finder.



No. 667,785. Patented Feb. l2, IQUL A. LIETZ.

COMPASS DEVIATION FINDER.

(Application filed June 9, 1898.\

(No Model.

we NORRYS PEYER5 w. PNOTO LIYHO- WASHINGTON. n. c.

T FFICe Sterne are ADOLPH LIETZ, OF SAN FRANCISCO, CALIFORNIA, ASSIGNORTO THE A. LIETZ COMPANY, OF SAME PLACE.

COMPASS=DEVIATHON FINDER.

forming part of Letters Patent No. 667,785, dated February 12, 1901.

Application filed June 9, 1898. Serial No. 682,983. (No model.)

To all 1071mm, it may concern: which the latitudearc plays, and uponsaid Beitknown that I, ADOLPH LIETZ, acitizen clamp is a fixedindex-mark ct. of the United States, residing at the city and Theinstrument can either be placed dicounty of San Francisco, in the Stateof Oalirectly on top of the compass or on a dumb- 5 fornia, haveinvented certain new and useful card E, which is hung in rings like thecom- Improvements in Compass-Deviation Findpass. ers; and I do herebydeclare the following to In manipulating the instrument it is only be afull, clear, and exact description of the necessary to set thelatitude-arc so that the same. mark representing the latitude of theplace I0 My invention relates to that class of instru- Where theobservation is being taken, which ments for finding or determining thevarialatitude is known or has already been ascertion or deviation of thecompass, in which the tained, shall aline with the fixed index-mark truemeridian is ascertained by the adjusta. Then fix it by the clamp a. Nowturn ment of connected latitude and time arcs or the instrument in ahorizontal plane until 15 rings to the latitude of the place where thethe shadow of the thread or wire E falls upon observation is being takenand to the apparthat division of the hour-arc which correent time.sponds with the apparent time, which has The object of my invention isto simplify been ascertained. The latitude-arc and the instruments ofthis character and to accomthread or wire will now liein the plane ofthe 2o plish the result of ascertaining the deviation true meridian,from which the deviation of by bearings of the heavenly bodies,princiany compass can be readily ascertained by pally the sun, withoutthe use of tables in a comparing it with the plane of the latitudesimpleand accurate manner. arc as thus set.

My invention is embodied in the novel In order to find the magneticmeridian, the 25 parts and arrangement and combinations of base-plate Ais mounted on the compass or parts hereinafter described, andparticularly card on a central pivot f, and said plate is set forth inthe claims. provided with a pointer a It has also a slot Figure 1 is anelevation of my deviationa in which works a thumb-screw f. Now finder.Fig. 2 is a plan of same. Fig. 3 is turn thebase-plate on its pivotuntilits pointer 0 a detail of the connection between the two indicatesthe point on the compass or card corarcs. Fig. 4: is a detail of thereading-card responding to the magnetic variation of the on thehour-arc. place where the observation is being taken, A is a base-plate,from which rise standand thereclamp said platebythethumb-screw ards ofsuitable shape. (Here shown as a f. Then manipulate the instrument asbe- 5 forked casting In these standards is pivfore, and while thelatitude-arc will lie in the oted at b the arc C, which is divided intoplane of the true meridian the course indihours and subdivisions ofequal spaced discated by the compass or dumb-card is magtances,beginning with the noon-hour in the netic. center, and thence up eachside to the eX- In order to see the shadow cast bythe thread 4otremities. This are is the hour-arc. Dis anor wire E with greatercertainty than its apother are graduated in degrees of latitude, itspearance on the hour-arc adords, I fit to said two quadrants beingnumbered from 0 to are a sliding bracket G, carrying a lined card 90,one representing the southern and the g, as is shown in Fig. 4. Thisbeing set other the northern latitude. This are is the properly tocorrespond to the division of ap 5 45 latitude-arc, and it is secured tothe hour-arc parent time, the shadow of the thread or wire in a plane atright angles thereto and passes being continued upon said card can beseen through the noon-hour of said arc. with certainty, thus avoidingpossible error In the line of a chord of the latitude-arc of reading. Asthe system of connected arcs and fixed to said are is a thread or wireE, in must be set to correspond to different lati- 50 position to throwa shadow on the hour-arc. tudes, it is obvious that by reason of itschang- On the base-plate A is a clamp a, through ing position thenicely-hung compass or dumbcard will be thrown out of balance and willnot remain horizontal. To obviate this, I eX- tend from the base-plate Aan arm (1, upon which I set a slidable weight W. By setting this weightthe proper balance may be maintained, as will be indicated by the levelsH.

This instrument thus admits of finding the true or the magnetic meridianor bearings therefrom by means of a sun-dial adjustable to the change oflatitude and so constructed that the divisions of the hour-arc areequally spaced.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a compass-deviation finder, the combination of a standard, anhour-arc piece movably supported thereby, a latitude-arc piece securedto the hour-arc piece, a shadowthrowing means, aclamp-arm extending fromIn witness whereof I have hereunto set my hand.

, ADOLPH LIETZ. Witnesses:

WALTER F. VANE, D. B. RICHARDS.

